Repair and strengthening system for reinforced concrete structure

ABSTRACT

A repair and strengthening system for a reinforced concrete structure has a ribbed steel plate, and a filler. The ribbed steel plate is disposed facing a strengthened area with a predetermined space therebetween. The strengthened area is an area to be strengthened in a structure surface that is a surface of a reinforced concrete structure. The filler is injected in the space between the structure surface and the ribbed steel plate. Ribs are formed on the ribbed steel plate by hot rolling. The ribs protrude from a steel-plate front face that is a side of the ribbed steel plate facing the structure surface.

TECHNICAL FIELD

The present invention relates to a repair and strengthening system for areinforced concrete structure, in particular, a repair and strengtheningsystem for a reinforced concrete structure which repairs or strengthensthe reinforced concrete structure portion of civil engineeringstructures and architectural structures.

BACKGROUND ART

Hitherto, many civil engineering structures (such as beams, floor slabs,bent in landing piers, bridges, concrete lining of tunnels/shafts, boxculverts, retaining walls, and caissons) and architectural structures(floor slabs, beams, and columns in large complex buildings or simpleroofed and walled structures, chimneys, and silos) have been constructedin reinforced concrete.

Recent years have seen an increase in the number of strengthening worksfor strengthening existing reinforced concrete structures. Thesestrengthening works are undertaken for purposes such as ensuring safetyagainst powerful earthquakes under consideration such as the Great EastJapan Earthquake and the Nankai Trough Earthquake, and ensuring safetyagainst loads exceeding those originally envisioned at the time ofconstruction due to increases in vehicle weight as well as widening orextension of roads.

Further, many reinforced concrete structures constructed in the pasthigh growth era are now undergoing deterioration, giving rise to theneed for repair and life extension works to extend the life of thesestructures.

As an efficient method to execute such repair and strengthening ofreinforced concrete structures, a “steel-plate strengthening technique”has been used in related art. In this method, a steel plate is installedonto the surface of an existing reinforced concrete structure by usingan anchor bolt or the like, a filler is injected into the space createdbetween the surface of the reinforced concrete structure and the steelplate to integrate the reinforced concrete structure and the steel platetogether, and repair and strengthening is performed in this state.

According to this method, the steel plate functions as formwork forinjecting the filler, and also doubles as a steel reinforcement, thuscutting down the processes of rebar arrangement and formwork dismantlingwhich are required for repair and strengthening. Because the work periodcan be shortened and cost can be reduced as a result, this method isused for many repair and strengthening works.

For the repair and strengthening effect of this method to be fullyrealized, it is necessary to ensure the reliability of theabove-mentioned integration, and ensure that the force generated in thereinforced concrete structure is reliably transferred to the steelplate. For example, measures taken to this end include: carefullyremoving rust or dust on the surface of the steel plate to improve theadhesion between an adhesive filler and the steel plate; mounting a“shear connector” such as a stud bolt to the steel plate to improvetransfer of force between a grout filler and the steel plate; andsecuring the steel plate in place with an anchor bolt anchored to thereinforced concrete structure, to directly transfer force to the steelplate (at this time, force is transferred by means of the shear actingon the anchor bolt).

Accordingly, a steel-plate bonding technique using an adhesive (epoxy)filler has been disclosed, which allows use of a plated steel plate withgood corrosion resistance, and can simplify complicated pretreatment orcoating process in comparison to related art (see, for example, PatentLiterature 1).

Further, a seismic strengthening system for a reinforced concretestructure that uses a grout filler has been disclosed, which allows thesteel plate to be easily attached to the concrete framework, and ensuresthat the grout spreads throughout the space between the concreteframework and the steel plate (see, for example, Patent Literature 2).

CITATION LIST Patent Literature

[Patent Literature 1] Japanese Unexamined Patent Application PublicationNo. 2012-107398 (pages 9 and 10, FIG. 3)

[Patent Literature 2] Japanese Unexamined Patent Application PublicationNo. 2013-189782 (pages 3 and 4, FIG. 2)

SUMMARY OF INVENTION Technical Problem

However, the invention (adhesive filler) described in Patent Literature1 has the following problems.

(a) To protect the steel plate against corrosion by means of plating orcoating, special treatment is required to make the roughness of itssurface suitable for the bonding process.

(b) The condition (such as dust, dirt, or wetness) of the steel platesurface greatly affects the bond strength, and hence it is critical tocontrol the quality of execution of work (to be also simply referred toas “execution” hereinafter). In particular, many repair andstrengthening works are executed at sites that are narrow spaces to workin, making it difficult to ensure reliable quality.

(c) There is a problem of how to assure the quality of the resin usedfor bonding over the long term. For instance, deterioration of resin hasbeen pointed out as a possible cause of the pulling out of anchor boltsused to secure the ceiling slabs of the Sasago tunnel. As demonstratedby this incident, factors such as long-term temperature changes, stress,dryness/wetness, and chemical actions cause the strength of bond withthe steel plate to decrease, which is increasingly presenting a problemin terms of reliability.

Further, the invention (grout filler) described in Patent Literature 2has the following problems.

(d) It is necessary to use a stud bolt, an anchor bolt, or athrough-bolt to integrate the steel plate with an existing concretestructure so that the steel plate exerts its function, and significantamounts of time, machinery and materials, and cost are required toexecute this work.

(e) If an anchor bolt or a through-bolt is used, the position to installthe bolt is restricted in order to avoid interference with the rebar ofan existing reinforced concrete structure. Depending on the case, thismakes appropriate designing or execution impossible, or makes itimpossible to employ this method.

(f) If a stud bolt is installed to the steel plate, the space betweenthe surface of the existing reinforced concrete structure and the steelplate needs to be made larger than the length of the stud bolt,resulting in an increase in the area to be strengthened. Consequently,depending on the case, the amount (volume) of the grout to be injectedincreases, leading to higher cost, or the weight of the portion to bestrengthened increases, which is structurally disadvantageous.

The present invention has been made to address the above problems.Accordingly, it is an object of the present invention to provide arepair and strengthening system for a reinforced concrete structurewhich can improve the delivery of force between a steel plate and afiller, without applying special surface treatment or meticulous surfacecleaning to the steel plate, or without installing a stud bolt or usingan anchor bolt for the steel plate.

Solution to Problem

(1) According to the present invention, there is provided a repair andstrengthening system for a reinforced concrete structure including asteel plate that is disposed with a predetermined space to a structuresurface, the structure surface being a surface of the reinforcedconcrete structure, and a filler that is injected in the space,

wherein a plurality of protrusions are formed on a steel-plate frontface that is a surface on one side of the steel plate, and thesteel-plate front face faces the structure surface.

(2) According to the present invention, there is provided a repair andstrengthening system for a reinforced concrete structure including asteel plate that is disposed with a predetermined space to a structuresurface, the structure surface being a surface of the reinforcedconcrete structure, and a filler that is injected in the space,

wherein a plurality of openings are formed in the steel plate, and theopenings are blocked by the filler.

(3) According to the present invention, there is provided a repair andstrengthening system for a reinforced concrete structure including asteel plate that is disposed in contact with a structure surface, and isprovided with a plurality of openings, the structure surface being asurface of the reinforced concrete structure, and a filler that blocksthe openings.

(4) In (3) above, a plurality of protrusions are formed on a steel-platefront face that is a surface on one side of the steel plate, and atleast one of the plurality of protrusions is in contact with thestructure surface.

(5) In (3) or (4) above, a plurality of protrusions are formed on asteel-plate back face that is a surface on another side of the steelplate, and the plurality of protrusions formed on the steel-plate backface are surrounded by the filler.

(6) In any one of (3) to (5) above, the repair and strengthening systemhas a plurality of the steel plates, and in one steel plate pair of thesteel plates, at least one of the openings of one steel plate and atleast one of the openings of another steel plate overlap each other, andthe one steel plate and the other steel plate are integrated together bythe filler injected in overlapping openings of the one steel plate andoverlapping openings of the other steel plate.

(7) In any one of (2) to (6) above, the plurality of openings are formedby enlarging a plurality of slits formed in the steel plate bystretching.

(8) In any one of (1), (4), (5), and (6) above, the plurality ofprotrusions are formed integrally when the steel plate is manufacturedby hot rolling.

(9) In (8) above, the plurality of protrusions are spaced by 30 mm to 40mm from each other, have a height of 2.5 mm to 5.0 mm, and have a widthof 4 mm to 20 mm, the width being a distance in a directionperpendicular to a direction of the hot rolling at a base of theprotrusions.

(10) In any one of (1) to (9) above, the steel plate is supported by ahang bolt, the hang bolt being installed in the reinforced concretestructure and projecting from the structure surface.

(11) In any one of (1) to (10) above, the reinforced concrete structureincludes the structure surface, and a pair of structure sides that arecontinuous with the structure surface,

the repair and strengthening system includes a steel-plate supportmember including a support horizontal member that is disposed inparallel to the structure surface, a pair of support vertical membersthat are disposed in parallel to the pair of structure sides, and asupporting bolt that is installed in the reinforced concrete structure,and projects from the pair of structure sides,

the steel-plate support member is installed onto the reinforced concretestructure with the supporting bolt that penetrates a vertical-memberthrough-hole formed in the pair of support vertical members, and

the steel plate is installed on the support horizontal member of thesteel-plate support member.

(12) In (11) above, the vertical-member through-hole is elongated in adirection perpendicular to the support horizontal member,

a height adjusting bolt is installed in the support vertical member, theheight adjusting bolt being movable in the direction perpendicular tothe support horizontal member and abutting against the supporting boltat a distal end, and

as the height adjusting bolt is turned, the steel-plate support memberis moved in a direction perpendicular to the structure surface.

(13) In (11) or (12) above, a guide projection is provided on asteel-plate back face, the steel-plate back face being a side oppositeto the steel-plate front face,

the support horizontal member is provided with a support-member guidegroove into which the guide projection enters, and

as the guide projection is guided by the support-member guide groove andmoves, the steel plate is able to move relatively with respect to thesteel-plate support member.

(14) In any one of (11) to (13) above, the support horizontal member andthe support vertical members are detachably coupled by a fastening bolt.

(15) In any one of (1) to (14), the steel plate includes a pair ofsteel-plate sidewall parts, the pair of steel-plate sidewall parts beingcontinuous with opposite side edges of the steel plate and formed on asame side as the steel-plate front face.

(16) In any one of (2) to (7) above, the steel plate is bent into aU-shape in section that includes a bottom portion and a pair of sideportions,

a bar member is installed to penetrate a structure through-hole formedin the reinforced concrete structure, and

as the bar member penetrates the openings, the steel plate is securedonto the reinforced concrete structure.

(17) In any one of (1) to (16) above, the steel plate is made of plainsteel, high tension steel, stainless steel, or weathering steel.

(18) In any one of (1) to (17) above, the filler is mortar,shrinkage-compensating mortar, polymer cement mortar, resin mortar,fiber reinforced concrete, superplasticized concrete, high-strengthconcrete, an epoxy resin injection material, a polyurethane resininjection material, or a sodium silicate injection material.

Advantageous Effects of Invention

The repair and strengthening system for a reinforced concrete structureaccording to the present invention has the following advantageouseffects.

(i) The plurality of protrusions are formed on the steel-plate frontface that faces the structure surface, and the filler is injected in thespace between the structure surface and the steel-plate front face.Consequently, the plurality of protrusions mechanically interlock withthe filler, allowing transfer of shear therebetween.

Accordingly, when a bending load acts on the reinforced concretestructure, the steel plate behaves integrally with the reinforcedconcrete structure. Consequently, the tensile stress at the structuresurface is shared by the steel plate, thereby strengthening thecorresponding area. If this area is damaged, this damage is repaired.

(ii) Further, the filler injected in the space between the structuresurface and the steel plate blocks the plurality of openings formed inthe steel plate. Consequently, the filler mechanically interlocks withthe plurality of protrusions, allowing transfer of shear therebetween.Therefore, the same effect as (i) above is obtained.

(iii) In the repair and strengthening system for a reinforced concretestructure according to the present invention, the filler is injected inthe openings of the steel plate that is disposed in contact with thestructure surface. Consequently, the openings of the steel plate (moreprecisely, the areas of the steel plate surrounding the openings)mechanically interlock with the filler, allowing transfer of sheartherebetween. Therefore, the same effect as (i) above is obtained.

(iv) The protrusions formed on the steel-plate back face are surroundedby the filler, allowing strong adhesion between the steel plate and thefiller. Therefore, the same effect as (i) above is obtained.

(v) A pair of steel plates partially overlap, and the pair of steelplates are integrated together by means of the filler injected in therespective openings of the steel plates in the overlapping area. Thiseliminates the need to couple the pair of steel plates together bywelding or by using a coupling member, thereby facilitating execution.The term “integration” as used in the present invention refers to astate in which force is transferred between steel plates, and includes acase where the steel plates partially overlap each other, and a casewhere the steel plates are not in direct contact with each other.

(vi) The openings are formed by enlarging the plurality of slits bystretching, allowing easy workability and reduction of the executioncost and the execution period.

(vii) The steel plate provided with the protrusions is manufactured byhot rolling. Consequently, there is no special working required in thefactory that prepares the components or at the work site, allowingreduction of the execution cost and the execution period.

(viii) The steel plate is supported by the hang bolt that projects fromthe structure surface. The hang bolt is not used for the purpose oftransferring the force acting on the reinforced concrete structure tothe steel plate, and there is no need for a shear anchor bolt totransfer the force acting on the reinforced concrete structure to thesteel plate. The number of components thus decreases, leading to lowercomponents cost. Further, drilling required for installing a shearanchor bolt is unnecessary. Therefore, no drilling equipment isrequired, and the ease of execution at narrow space work sites improves,allowing reduction of the execution cost and the execution period.

(ix) The steel plate is installed on the support horizontal member ofthe steel-plate support member that includes the support horizontalmember and the pair of support vertical members, and the pair of supportvertical members are supported by the supporting bolt installed to thesides of the structure. Consequently, installation of the supportingbolt is easy, thus improving the ease of execution.

(x) Further, as the height adjusting bolt is turned, the steel-platesupport member is moved in the direction perpendicular to the structuresupport. This facilitates execution, and also improves the accuracy withwhich the steel-plate support member is positioned with respect to thedirection perpendicular to the structure surface.

(xi) As the guide projection is guided by the support-member guidegroove and moves, the steel plate is able to move relatively withrespect to the steel-plate support member. This facilitates execution,and also improves the accuracy with each the steel-plate support memberis positioned with respect to the direction parallel to the structuresurface.

(xii) The support horizontal member and the support vertical members aredetachably coupled by the fastening bolt to allow for easy storage andtransport, reducing the execution cost.

(xiii) Further, the steel plate includes the pair of steel-platesidewall parts, thus functioning as formwork when injecting the filler.Consequently, installation and dismantling of formwork are unnecessary,allowing reduction of the work period and cost.

(xiv) The steel plate including the openings is bent into a U-shape insection, and as the bar member installed in the reinforced concretestructure penetrates the openings, the steel plate is secured onto thereinforced concrete structure. Consequently, execution is facilitated,and execution cost can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C illustrate a strengthening example for explaining arepair and strengthening system for a reinforced concrete structureaccording to Embodiment 1 of the present invention, in which FIG. 1A isa partially see-through front view, FIG. 1B is a sectional side viewtaken along A-A in FIG. 1A, and FIG. 1C is a sectional side view takenalong B-B in FIG. 1A.

FIG. 2 is an enlarged front view of a part of a steel plate constitutingthe repair and strengthening system for a reinforced concrete structureillustrated in FIGS. 1A to 1C.

FIG. 3A to 3D illustrate a repair example for explaining the repair andstrengthening system for a reinforced concrete structure according toEmbodiment 1 of the present invention, in which FIG. 3A is a partiallysee-through front view, FIG. 3B is a partially enlarged, partiallysee-through front view, FIG. 3C is a sectional side view taken along A-Ain FIG. 3A, and FIG. 3D is a sectional side view taken along B-B in FIG.3A.

FIG. 4A to 4C illustrate a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 2 of the present invention, in which FIG. 4A is a partiallysee-through front view, FIG. 4B is a sectional side view taken along A-Ain FIG. 4A, and FIG. 4C is a sectional side view taken along B-B in FIG.4A.

FIGS. 5A and 5B illustrate a repair and strengthening system for areinforced concrete structure according to Embodiment 3 of the presentinvention, in which FIG. 5A is a partially enlarged, partiallysee-through front view, and FIG. 5B is a partially enlarged sidesectional view.

FIGS. 6A and 6B illustrate a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 4 of the present invention, in which FIG. 6A is a partiallyenlarged, partially see-through front view, and FIG. 6B is a partiallyenlarged side sectional view.

FIGS. 7A and 7B illustrate a steel plate used for the repair andstrengthening system for a reinforced concrete structure illustrated inFIGS. 6A and 6B, in which FIG. 7A is a partially enlarged, partiallysee-through front view, and FIG. 7B is a partially enlarged side view.

FIGS. 8A to 8C illustrate a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 5 of the present invention, in which FIG. 8A is a partiallysee-through front view, FIG. 8B is a sectional side view taken along A-Ain FIG. 8A, and FIG. 8C is a sectional side view taken along B-B in FIG.8A.

FIGS. 9A and 9B illustrate a steel plate used for the repair andstrengthening system for a reinforced concrete structure according toEmbodiment 5 of the present invention, in which FIG. 9A is an enlarged,partially see-through front view of a part of the steel plate, and FIG.9B is an enlarged side view of a part of the steel plate.

FIGS. 10A to 10C illustrate a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 6 of the present invention, in which FIG. 10A is a partiallysee-through front view, FIG. 10B is a sectional side view taken alongA-A in FIG. 10A, and FIG. 10C is a bottom view illustrating the repairexample.

FIGS. 11A to 11C illustrate a steel plate used for the repair andstrengthening system for a reinforced concrete structure according toEmbodiment 6 of the present invention, in which FIG. 11A is an explodedplan view of the steel plate, FIG. 11B is a plan view of an originalplate prior to being worked into the steel plate, and FIG. 11C is anenlarged plan view of a part of the original plate prior to being workedinto the steel plate.

FIGS. 12A to 12E illustrate another form of the steel plate used for therepair and strengthening system for a reinforced concrete structureaccording to Embodiment 6 of the present invention, in which FIG. 12A isa plan view, FIG. 12B is a sectional view taken along B-B in FIG. 12A,FIG. 12C is a sectional view taken along C-C in FIG. 12A, FIG. 12D is aplan view of an original plate prior to being worked into the steelplate, and FIG. 12E is a sectional view taken along A-A in FIG. 12D.

FIGS. 13A and 13B illustrate another form of the steel plate used forthe repair and strengthening system for a reinforced concrete structureaccording to Embodiment 6 of the present invention, in which FIG. 13A isa plan view, and FIG. 13B is a plan view of an original plate prior tobeing worked into the steel plate.

FIG. 14 is a perspective view of a components kit used for a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 7 of the present invention.

FIG. 15 is a partially see-through front view for explaining a repairand strengthening system for a reinforced concrete structure accordingto Embodiment 8 of the present invention.

FIG. 16 is a partially see-through front view of a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 9 of the present invention.

FIGS. 17A and 17B illustrate a repair and strengthening system for areinforced concrete structure according to Embodiment 10 of the presentinvention, in which FIG. 17A is a partially see-through front view, andFIG. 17B is a perspective view of a part of the repair and strengtheningsystem.

DESCRIPTION OF EMBODIMENTS Embodiment 1

A repair and strengthening system for a reinforced concrete structureaccording to Embodiment 1 of the present invention is used to repair orstrengthen a reinforced concrete structure. Hereinafter, a strengtheningexample will be described with reference to FIGS. 1 and 2, and a repairexample will be described with reference to FIG. 3.

(Strengthening Example)

FIGS. 1 and 2 illustrate a strengthening example for explaining therepair and strengthening system for a reinforced concrete structureaccording to Embodiment 1 of the present invention. FIG. 1A is apartially see-through front view, FIG. 1B is a sectional side view takenalong A-A in FIG. 1A, and FIG. 1C is a sectional side view taken alongB-B in FIG. 1A. FIG. 2 is an enlarged front view of a part of a steelplate. These figures are schematic only, and not intended to limit thepresent invention to the particular forms (such as shapes or quantities)illustrated.

In FIG. 1, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 100 strengthens a reinforced concrete structure 10.

The reinforced concrete structure 10 is a floor, a beam, or a column.The reinforced concrete structure 10 includes concrete 11 placed in aplanar fashion, rebars 12 that are disposed in parallel to each otheralong the longitudinal direction (left-right direction in FIG. 1A)within the concrete 11, and a hoop reinforcement 13 that is disposed ina perpendicular plane (vertical plane in FIG. 1A) with respect to therebars 12 so as to surround the rebars 12 within the concrete 11.

A predetermined area of a surface on one side (to be referred to as“structure surface 14” hereinafter) of the concrete 11 is referred to asstrengthened area 15. While in FIG. 1A the strengthened area 15 isdepicted as a surface with minute irregularities in order to clearlyindicate the strengthened area 15, the present invention is not limitedto this. The strengthened area 15 may be flat instead. For example, thestrengthened area 15 may be an area where a relatively large bendingmoment acts.

In the concrete 11, a hang bolt 40 is installed (post-installed) intothe strengthened area 15 of the concrete 11. A part of the hang bolt 40projects from the structure surface 14, and penetrates a through-hole 23formed in a steel plate (to be referred to as “ribbed steel plate”hereinafter) 20. A nut 41 is in threaded engagement with the hang bolt40. That is, by the composite mechanism of the hang bolt 40 and the nut41, the ribbed steel plate 20 is disposed facing the strengthened area15 (which is the same as a part of the structure surface 14) with apredetermined space 16 therebetween (so that the ribbed steel plate 20is unable to move or fall). The space 16 is filled with a filler 30.

(Steel Plate)

In FIG. 2, the ribbed steel plate 20 is about 9 mm to 25 mm inthickness, and its surface on one side (to be referred to as“steel-plate front face 21” hereinafter) is provided with a plurality ofprotrusions (to be referred to as “ribs” hereinafter) 22. The ribs 22are formed integrally by grooves formed in the surface of a reductionroll when the ribbed steel plate 20 is manufactured by hot rolling. Theribs 22 are spaced by 30 mm to 40 mm from each other in the direction atright angles to that of rolling (left-right direction in FIG. 2), have aheight of 2.5 mm to 5.0 mm, and have a width (the distance in thedirection at right angles to that of rolling) at the base of 4 mm to 20mm. The sectional shape of the ribs 22 is not limited to trapezoidal butmay be semicircular or rectangular.

The present invention is not intended to limit the constituent materialor the like of the ribbed steel plate 20. As long as the ribs 22 areformed by hot rolling, the ribbed steel plate 20 may be made of alloysteel such as plain steel (carbon steel), high tension steel, stainlesssteel, or weathering steel. Accordingly, the composition or the like ofthe ribbed steel plate 20 may be selected as appropriate in accordancewith the installation condition (load or environment such as weather).

In the following, for the convenience of explanation, the side oppositeto the steel-plate front face 21 is referred to as “steel-plate backface 24”.

(Filler)

Further, the present invention is not intended to limit the constituentmaterial or the like of the filler 30. Examples of grout filler includemortar, shrinkage-compensating mortar, polymer cement mortar, resinmortar, fiber reinforced concrete, superplasticized concrete, andhigh-strength concrete, and examples of adhesive filler include an epoxyresin injection material, a polyurethane resin injection material, and asodium silicate injection material. Accordingly, the composition or thelike of the filler 30 may be selected as appropriate in accordance withthe installation condition (load or environment such as weather).

(Operational Effects)

The structure surface 14 is a surface on which the tensile stress acts.The steel-plate front face 21 of the ribbed steel plate 20 faces thestructure surface 14. That is, the ribs 22 bite into the filler 30injected in the space 16 so that the ribs 22 mechanically interlock withthe filler 30, allowing transfer of shear therebetween. Further, thefiller 30 is in intimate contact with the strengthened area 15.

(a) Accordingly, when a bending load acts on the concrete 11, the ribbedsteel plate 20 behaves integrally with the concrete 11. Therefore, thetensile stress at the structure surface 14 is shared by the ribbed steelplate 20 in the strengthened area 15, and the strengthened area 15 isthus strengthened.

(b) At this time, as mentioned above, the ribs 22 mechanically interlockwith the filler 30, allowing transfer of shear therebetween. This meansthat factors such as the surface roughness of the steel-plate front face21, and dust or the like adhering to the steel-plate front face 21 donot cause strengthening to become inadequate, thus ensuring highreliability of strengthening.

(c) Because there is no need to provide a shear anchor bolt to transferthe force acting on the concrete 11 to the ribbed steel plate 20,components cost is reduced. Further, drilling required for installing ashear anchor bolt is unnecessary. Therefore, no drilling equipment isrequired, and the ease of execution at narrow space work sites improves,allowing reduction of the execution cost and the execution period.

(d) Because the ribbed steel plate 20 provided with the ribs 22 ismanufactured by hot rolling, there is no special working required in thefactory that prepares the components of the repair and strengtheningsystem 100 or at the work site, allowing further reduction of theexecution cost and the execution period.

(e) Further, the hang bolt 40 is not used for the purpose oftransferring the force acting on the concrete 11 to the ribbed steelplate 20. Accordingly, the hang bolt 40 may be a thin one, with justenough thickness to bear the self-weight of the ribbed steel plate 20.Further, the hang bolt 40 does not need to be located close to therebars 12 or the hoop reinforcement 13 to exchange forces with therebars 12 or the hoop reinforcement 13, ensuring high degree of freedomof the position to install the hang bolt 40.

(f) Moreover, the ribbed steel plate 20 itself functions as formworkwhen injecting the filler 30, thus eliminating costs associated with theinstallation and dismantling of formwork. In this respect as well,reduction of the execution cost and the execution period is facilitated.

(Repair Example)

FIG. 3 illustrates a repair example for explaining the repair andstrengthening system for a reinforced concrete structure according toEmbodiment 1 of the present invention, in which FIG. 3A is a partiallysee-through front view, FIG. 3B is a partially enlarged, partiallysee-through front view illustrating the repair example, FIG. 3C is asectional side view taken along A-A in FIG. 3A, and FIG. 3( d) is asectional side view taken along B-B in FIG. 3A. These figures areschematic only, and not intended to limit the present invention to theparticular forms (such as shapes or quantities) illustrated. Further,portions that are the same as or equivalent to those in FIG. 1 aredenoted by the same reference signs, and a description of these portionsis partially omitted.

In FIG. 3, the repair and strengthening system 100 repairs thereinforced concrete structure 10.

Corrosion or deterioration occurring in a predetermined area of thestructure surface 14 of the reinforced concrete structure 10 causes apart of the concrete 11 to dislodge, forming a damaged surface 17.Hereinafter, an area bounded by the structure surface 14 prior todislodging of the concrete 11, and the damaged surface 17 formed afterdislodging of the concrete 11 is referred to as a dislodged concreteportion 31. In the dislodged concrete portion 31, the rebars 12 arepartially exposed, and the exposed portion of the rebars 12 is corrodedand decreases in outside diameter. Hereinafter, the area where theoutside diameter of the rebars 12 decreases is referred to as a“corroded/deteriorated rebar portion 12 a”.

In the concrete 11, the hang bolt 40 is installed (post-installed) intothe damaged surface 17, with a part of the hang bolt 40 projecting fromthe structure surface 14 via the dislodged concrete portion 31. Then,the hang bolt 40 penetrates the through-hole 23 formed in the ribbedsteel plate 20, with the nut 41 being in threaded engagement with thehang bolt 40. At this time, the steel-plate back face 24 of the ribbedsteel plate 20 is located in the same plane as the structure surface 14.

That is, by the composite mechanism of the hang bolt 40 and the nut 41,the ribbed steel plate 20 is disposed in such a way that makes theribbed steel plate 20 unable to move or fall, while being containedwithin the dislodged concrete portion 31.

Further, the portion between the steel-plate front face 21 and thedamaged surface 17 (corresponding to the volume of the dislodgedconcrete portion 31 minus the volume of the ribbed steel plate 20) isfilled with the filler 30, with the result that thecorroded/deteriorated rebar portion 12 a is embedded in the filler 30.

(Operational Effects)

Accordingly, the repair and strengthening system 100 provides the sameoperational effects for repair as in the case of strengthening. At thistime, the force acting on the corroded/deteriorated rebar portion 12 ais shared mainly by the ribbed steel plate 20, resulting in repair ofstrength. Corrosion of the corroded/deteriorated rebar portion 12 a isarrested mainly by the filler 30, resulting in repair of deterioration.

Embodiment 2

FIG. 4 illustrates a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 2 of the present invention, in which FIG. 4A is a partiallysee-through front view, FIG. 4B is a sectional side view taken along A-Ain FIG. 4A, and FIG. 4C is a sectional side view taken along B-B in FIG.4A. Portions that are the same as or equivalent to those in Embodiment 1are denoted by the same reference signs, and a description of theseportions is partially omitted. Further, these figures are schematiconly, and not intended to limit the present invention to the particularforms (such as shapes or quantities) illustrated.

Repair Example

In FIG. 4, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 200 uses a steel-plate support member 50 that is squareU-shaped, instead of the hang bolt 40 of the repair and strengtheningsystem 100.

That is, the reinforced concrete structure 10 includes the structuresurface 14, and a pair of structure sides 18 that are continuous withthe structure surface 14. The reinforced concrete structure 10 has astructure through-hole 19 formed in parallel to the structure surface 14and spanning the pair of structure sides 18. At this time, the pair ofstructure sides 18 are perpendicular to the structure surface 14, andare parallel to each other. However, the present invention is notlimited to this. The pair of structure sides 18 may be non-parallel toeach other (V-shape) so that the distance between the pair of structuresides 18 increases with increasing distance from the structure surface14.

The steel-plate support member 50 includes a support horizontal member51 and a pair of support vertical members 52. The support horizontalmember 51 is disposed in parallel to the structure surface 14 (moreprecisely, facing the damaged surface 17). The pair of support verticalmembers 52 are disposed in parallel to the pair of structure sides 18. Avertical-member through-hole 53 is formed in each of the pair of supportvertical members 52.

The opposite end portions of a supporting bolt 60 that penetrates thestructure through-hole 19 project from the structure sides 18, andpenetrate the vertical-member through-hole 53. A nut 61 is in threadedengagement with either end of the supporting bolt 60. That is, thesteel-plate support member 50 is installed onto the reinforced concretestructure 10 with the supporting bolt 60 that penetrates the structurethrough-hole 19.

Further, the ribbed steel plate 20 is installed on the supporthorizontal member 51 of the steel-plate support member 50, with thesteel-plate front face 21 facing the damaged surface 17 (the steel-plateback face 24 is abutting against the support horizontal member 51). Thefiller 30 is injected into the portion between the steel-plate frontface 21 and the damaged surface 17 (which substantially corresponds tothe dislodged concrete portion 31).

Therefore, the repair and strengthening system 200 provides the sameoperational effects as the repair and strengthening system 100 withrespect to strength and deterioration.

Further, the hang bolt 40 is changed to the steel-plate support member50. Accordingly, the operation of erecting the hang bolt in an uprightposition is replaced by a relatively easy operation of boring thestructure through-hole 19 in the transverse direction, thus improvingthe ease of execution.

In the above example, the opposite end portions of the supporting bolt60 project from the structure sides 18. However, the present inventionis not limited to this. Another approach may be used in which thesupporting bolt 60 is divided into two parts, the structure through-hole19 is changed to a blind hole with a predetermined depth from thestructure sides 18, and each of the two divided parts of the supportingbolt is installed in the blind hole. Alternatively, the supporting bolt60 may be a bar member having male threads formed only at the ends.

The steel-plate support member 50 may be formed either by integratingthe support horizontal member 51 and the pair of support verticalmembers 52 together (for example, by bending a plate member, or bycutting light gauge steel with a square U-shaped section), or by joiningthree plate members together by welding or mechanically (such as by athread/threaded hole mechanism, or a fitting protrusion/fitting holemechanism).

Embodiment 3

FIG. 5 illustrates a repair and strengthening system for a reinforcedconcrete structure according to Embodiment 3 of the present invention,in which FIG. 5A is a partially enlarged, partially see-through frontview, and FIG. 5B is a partially enlarged side sectional view. Portionsthat are the same as or equivalent to those in Embodiments 1 and 2 aredenoted by the same reference signs, and a description of these portionsis partially omitted. Further, these figures are schematic only, and notintended to limit the present invention to the particular forms (such asshapes or quantities) illustrated.

In FIG. 5, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 300 makes it possible to adjust the position of thesteel-plate support member 50 in the repair and strengthening system 200for a reinforced concrete structure. Otherwise, the repair andstrengthening system 300 is the same as the repair and strengtheningsystem 200 for a reinforced concrete structure. Therefore, only theportion of the repair and strengthening system 300 that enables suchpositional adjustment will be described.

In the steel-plate support member 50 of the repair and strengtheningsystem 300, the vertical-member through-hole 53 is an elongated holethat is elongated in a direction perpendicular to the support horizontalmember 51, and a threaded hole 55 that reaches the vertical-memberthrough-hole 53 is provided at an end face (to be referred to as“vertical-member upper end face” hereinafter) 54 of the support verticalmembers 52 opposite to the support horizontal member 51. A heightadjusting bolt 71 is brought into threaded engagement with the threadedhole 55, with the distal end of the height adjusting bolt 71 abuttingagainst the supporting bolt 60.

Accordingly, turning the height adjusting bolt 71 causes the steel-platesupport member 50 to ascend or descend with respect to the supportingbolt 60.

Therefore, even if the structure through-hole 19 is not positionedaccurately (displaced) with respect to the vertical direction, byturning the height adjusting bolt 71, the steel-plate support member 50can be installed in its normal position.

Another approach may be used in which the steel-plate support member 50is installed in such a way that the support horizontal member 51 islocated at a low position away from the structure surface 14, and inthis state, the ribbed steel plate 20 is moved in parallel to thestructure surface 14 and slid onto the support horizontal member 51, andthen the height adjusting bolt 71 is turned to lift the ribbed steelplate 20 to the normal position.

Therefore, the repair and strengthening system 300 further facilitatesexecution, and makes it possible to further promote the operationaleffects of the repair and strengthening system 200.

In FIG. 5, a spacer 63 is disposed between each of the structure sides18 and each of the support vertical members 52, and the nut 61 presseseach of the support vertical members 52 against each of the structuresides 18 via a fastening washer 62.

Embodiment 4

FIGS. 6 and 7 illustrate a repair and strengthening system for areinforced concrete structure according to Embodiment 4 of the presentinvention, in which FIG. 6A is a partially enlarged, partiallysee-through front view, FIG. 6B is a partially enlarged side sectionalview, FIG. 7A is an enlarged, partially see-through front view of a partof a steel plate, and FIG. 7B is an enlarged side view of a part of thesteel plate. Portions that are the same as or equivalent to those inEmbodiments 1 and 2 are denoted by the same reference signs, and adescription of these portions is partially omitted. Further, thesefigures are schematic only, and not intended to limit the presentinvention to the particular forms (such as shapes or quantities)illustrated.

In FIG. 7, the steel-plate back face 24 of the ribbed steel plate 20 isprovided with a guide projection 25 extending in the longitudinaldirection. The guide projection 25 is substantially trapezoidal insection, and becomes wider with increasing distance from the steel-plateback face 24.

In FIG. 6, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 400 has a guide groove 56 provided in the supporthorizontal member 51 of the steel-plate support member 50 of the repairand strengthening system 200 for a reinforced concrete structure. Theguide groove 56 is wider at the back (bottom) than at its mouth.

Then, with the steel-plate back face 24 of the ribbed steel plate 20abutting against the support horizontal member 51, the guide projection25 enters the guide groove 56 in such a way that makes the guideprojection 25 able to move in the longitudinal direction and unable tomove out of position in the vertical direction.

Therefore, even if the structure through-hole 19 is not positionedaccurately (displaced) with respect to the longitudinal direction, byplacing the ribbed steel plate 20 on the support horizontal member 51,and moving the ribbed steel plate 20 in the longitudinal direction, theribbed steel plate 20 can be disposed at its normal position. At thistime, the position in the widthwise direction is maintained by thecomposite mechanism of the guide projection 25 and the guide groove 56.

Therefore, the repair and strengthening system 400 further facilitatesexecution, and makes it possible to further promote the operationaleffects of the repair and strengthening system 200.

In FIG. 6, the support horizontal member 51 and the support verticalmembers 52 are detachable from each other. A threaded hole 57 isprovided at the side end face of the support horizontal member 51, and athrough-hole 58 is provided in a lower end portion of each of thesupport vertical members 52. A fastening bolt 72 penetrates thethrough-hole 58 and comes into threaded engagement with the threadedhole 57, thus forming the steel-plate support member 50. Accordingly,the support horizontal member 51 and the support vertical members 52 canbe brought to the work site in a detached state, and used to easilyconstruct the steel-plate support member 50 on site, thus allowing easystocking and transport, which contributes to lower cost of execution asa result.

Each of the support vertical members 52 has a vertical-member lockingportion 59 provided in a lower end portion for locking engagement with apart of the side edge of the support horizontal member 51. In thevertical-member locking portion 59, the load exerted on the supporthorizontal member 51 is transferred to the support vertical members 52.Therefore, no shear acts on the fastening bolt 72.

The guide groove 56 may be provided in the support horizontal member 51of the steel-plate support member 50 that is not of a detachable typebut is formed integrally.

Embodiment 5

FIGS. 8 and 9 illustrate a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 5 of the present invention, in which FIG. 8A is a partiallysee-through front view, FIG. 8B is a sectional side view taken along A-Ain FIG. 8A, FIG. 8C is a sectional side view taken along B-B in FIG. 8A,FIG. 9A is an enlarged, partially see-through front view of a part of asteel plate, and FIG. 9B is an enlarged side view of a part of the steelplate.

Portions that are the same as or equivalent to those in Embodiments 1and 2 are denoted by the same reference signs, and a description ofthese portions is partially omitted. Further, these figures areschematic only, and not intended to limit the present invention to theparticular forms (such as shapes or quantities) illustrated.

In FIG. 9, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 500 uses a steel plate with sidewall 80. The steel platewith sidewall 80 includes a pair of steel-plate sidewall parts 26. Thepair of steel-plate sidewall parts 26 are continuous with the oppositeside edges of the ribbed steel plate 20, and function as a sideformwork.

In FIG. 8, the upper ends of the steel-plate sidewall parts 26 of thesteel plate with sidewall 80 are located above the damaged surface 17,and upper end portions of the steel-plate sidewall parts 26 abut againstthe structure sides 18. Accordingly, the dislodged concrete portion 31is surrounded by the steel-plate front face 21, and the pair ofsteel-plate sidewall parts 26 (more precisely, the faces of the pair ofsteel-plate sidewall parts 26 which are located on the dislodgedconcrete portion 31 side).

(Steel Plate with Sidewall)

That is, the upper ends of the steel-plate sidewall parts 26 of thesteel plate with sidewall 80 are located above the damaged surface 17,and the upper end portions of the steel-plate sidewall parts 26 abutagainst the structure sides 18. Accordingly, the dislodged concreteportion 31 is surrounded by the ribbed steel plate 20, and the pair ofsteel-plate sidewall parts 26 (more precisely, the faces of the pair ofsteel-plate sidewall parts 26 which are located on the dislodgedconcrete portion 31 side).

Therefore, the steel-plate sidewall parts 26 function as formwork wheninjecting the filler 30, thus eliminating the need to install formworkon the lateral side (widthwise direction) of the dislodged concreteportion 31. Therefore, installation and dismantling of formwork isunnecessary, allowing easier and quicker execution.

That is, according to the repair and strengthening system 500, inaddition to the same operational effects as the repair and strengtheningsystem 200, the improved ease of execution makes it possible to reducethe execution cost.

The steel plate with sidewall 80 may be used not only in Embodiment 2but also in any one of Embodiments 1, 3, and 4. When used in any one ofthese embodiments, the steel plate with sidewall 80 provides the sameoperational effects as those when the steel plate with sidewall 80 isused in Embodiment 2.

Embodiment 6

FIGS. 10 and 11 illustrate a repair example for explaining a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 6 of the present invention, in which FIG. 10A is a partiallysee-through front view, FIG. 10B is a sectional side view taken alongA-A in FIG. 10A, FIG. 10C is a bottom view illustrating the repairexample, FIG. 11A is an exploded plan view of a steel plate, FIG. 11B isa plan view of an original plate prior to being worked into the steelplate, and FIG. 11C is an enlarged plan view of a part of the originalplate prior to being worked into the steel plate.

Portions that are the same as or equivalent to those in Embodiments 1and 2 are denoted by the same reference signs, and a description ofthese portions is partially omitted. Further, these figures areschematic only, and not intended to limit the present invention to theparticular forms (such as shapes or quantities) illustrated.

Repair Example

In FIG. 10, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 600 uses a steel plate (to be referred to as “steel gridplate” hereinafter) 90.

The steel grid plate 90 has a plurality of openings 93 formed in a flatsteel plate (original plate). The steel grid plate 90 is bent into asquare U-shape in section including a bottom portion 97 and a pair ofside portions 98.

The structure through-hole 19 is formed in the reinforced concretestructure 10. Opposite end portions of a bar member (to be referred toas “PC bar steel” hereinafter) 67 that penetrates the structurethrough-hole 19 project from the structure sides 18.

The bottom portion 97 of the steel grid plate 90 is disposed in parallelto the structure surface 14, and the side portions 98 are disposed inparallel to the structure sides 18. In this state, the steel grid plate90 surrounds the dislodged concrete portion 31. At this time, oppositeend portions of the PC bar steel 67 penetrate the corresponding openings93, with a nut 68 being in threaded engagement with a threaded portionformed at either end of the PC bar steel 67. Therefore, the steel gridplate 90 is held at a predetermined position by the PC bar steel 67. Atthis time, the PC bar steel 67 penetrates a washer 69. That is, thewasher 69 is pressed against a grid portion 94 between the openings 93,and is installed in place with the nut 68 in such a way that the washer69 is unable to move out of position.

Further, the filler 30 is injected into the dislodged concrete portion31 surrounded by the steel grid plate 90, and the filler 30 blocks theopenings 93. That is, the filler 30 is a high-viscosity filler, forexample, a polymer cement mortar, which is sprayed onto the dislodgedconcrete portion 31 through the openings 93.

In the above example, the steel grid plate 90 is bent for use. However,the present invention is not limited to this. The steel grid plate 90may be used in its original flat form prior to being bent, as asubstitute for the ribbed steel plate 20 of the repair and strengtheningsystem 100.

(Steel Grid Plate)

In FIG. 11A, the steel grid plate 90 includes the plurality of openings93 (corresponding to the square cells of a checkerboard) arranged in apattern of squares, and the grid portion 94 (corresponding to the linesof a checkerboard) that is the tangible, physical portion between theopenings 93 that are empty spaces.

The steel grid plate 90 is formed by, for example, in-plane stretchingof an original plate 91 (see FIG. 11B) in which a plurality of slits 92(see FIG. 11C) are machined by a laser or the like. As the slits 92expand, the plurality of openings 93 are formed, and the discontinuousportions between the slits 92 become the grid portion 94 between theopenings 93.

In the above example, the discontinuous portions between the slits 92are arranged in the original plate 91 in a pattern of squares, formingthe openings 93 of a rectangular shape including sides that are parallelto the side edges of the steel grid plate 90, and sides that areperpendicular to the side edges of the steel grid plate 90. However, thepresent invention does not limit the shape of the openings 93. Forexample, the discontinuous portions between the slits 92 may be arrangedin a staggered fashion, forming the openings 93 of a rhombic shapeincluding sides that are inclined with respect to the side edges of thesteel grid plate 90.

(Operational Effects)

As described above, the repair and strengthening system 600 uses thesteel grid plate 90 instead of the steel plate with sidewall 80.Therefore, as mentioned above, the openings 93 are blocked by the filler30 injected in the dislodged concrete portion 31, and the filler 30bites into and mechanically interlocks with the openings 93, allowingtransfer of shear therebetween. Further, the filler 30 is in intimatecontact with the damaged surface 17 where a part of the concrete 11becomes dislodged and exposed.

(a) Accordingly, when a bending load acts on the concrete 11, the steelgrid plate 90 behaves integrally with the concrete 11. Therefore, therepair and strengthening system 600 provides the same operationaleffects as the repair and strengthening system 100.

(b) At this time, factors such as the surface roughness of the originalplate 91, and dust or the like adhering to the original plate 91 do notcause repair or strengthening to become inadequate, ensuring highreliability of repair and strengthening.

(c) Because supporting means such as the steel-plate support member 50is unnecessary, components cost is reduced. Further, drilling requiredfor installing a shear anchor bolt is unnecessary. Therefore, nodrilling equipment is required, and the ease of execution at narrowspace work sites improves, allowing reduction of the execution cost andthe execution period.

(d) In comparison to the steel plate with sidewall 80, the steel gridplate 90 is lightweight, is easy to store and transport, and also allowseasy handling at the time of work execution, resulting in low executioncost.

(e) The openings 93 of the steel grid plate 90 are blocked by the filler30 injected in the dislodged concrete portion 31. Accordingly, byinspecting the condition of the filler 30 blocking the openings 93, thecondition of the filler 30 injected in the dislodged concrete portion 31(such as whether proper filling has been achieved, or aging) can bemonitored.

(f) The dislodged concrete portion 31 can be filled with the filler 30by spraying the filler 30 onto the dislodged concrete portion 31 via theopenings 93 (the same as the space between adjacent portions of the gridportion 94). Therefore, there is a wide choice of options for executingwork, thus making it possible to keep the cost of execution low.

If the filler 30 has low viscosity, the steel grid plate 90 does notfunction as formwork. Therefore, it is necessary to impart the filler 30with a sufficient viscosity for keeping the filler 30 from flowing outfrom the openings 93.

(Another Form of Steel Grid Plate)

FIG. 12 illustrates another form of a steel plate used for the repairand strengthening system for a reinforced concrete structure accordingto Embodiment 6 of the present invention, in which FIG. 12A is a planview, FIG. 12B is a sectional view taken along B-B in FIG. 12A, FIG. 12Cis a sectional view taken along C-C in FIG. 12A, FIG. 12D is a plan viewof an original plate prior to being worked into the steel plate, andFIG. 12E is a sectional view taken along A-A in FIG. 12D. Portions thatare the same as or equivalent to those in FIG. 11 are denoted by thesame reference signs, and a description of these portions is partiallyomitted.

In FIG. 12E, the slits 92 machined in the original plate 91 are notperpendicular to the plane of the original plate 91. Instead, opposingslits 92 have a V-shape in section.

Consequently, when the slits 92 are stretched in parallel to the planeof the original plate 91, the grid portion 94 having a trapezoidal shapein section, and the openings 93 surrounded by the grid portion 94 areformed as illustrated in FIG. 12B and FIG. 12C.

Therefore, the interlocking between the filler 30 and the steel gridplate 90 improves.

(Another Form of Steel Grid Plate)

FIG. 13 illustrates another form of a steel plate used for the repairand strengthening system for a reinforced concrete structure accordingto Embodiment 6 of the present invention, in which FIG. 13A is a planview, and FIG. 13B is a plan view of an original plate prior to beingworked into the steel plate. Portions that are the same as or equivalentto those in FIG. 11 are denoted by the same reference signs, and adescription of these portions is partially omitted.

In FIG. 13B, the slits 92 machined in the original plate 91 are formednot linearly but in the shape of rectangular waves. Consequently, eitherside face of the grid portion 94 illustrated in FIG. 13A is formed notlinearly but in the shape of rectangular waves. That is, the gridportion 94 is provided with a plurality of protrusions that protrudetoward the openings 93, thus improving the interlocking between thefiller 30 and the steel grid plate 90.

The slits 92 illustrated in FIG. 13B may be formed as slits that havethe shape of rectangular waves and are not perpendicular to the plane ofthe original plate 91, like the slits 92 illustrated in FIG. 12E,thereby further improving the interlocking between the filler 30 and thesteel grid plate 90.

Embodiment 7

FIG. 14 is a perspective view of a components kit used for a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 7 of the present invention. In FIG. 14, individual componentsare detached, and disposed at positions close to those in actual use.Portions that are the same as or equivalent to those in Embodiments 3 to6 are denoted by the same reference signs, and a description of theseportions is partially omitted. Further, FIG. 14 is schematic only, andnot intended to limit the present invention to the particular forms(such as shapes or quantities) illustrated.

In FIG. 14, a components kit for a repair and strengthening system for areinforced concrete structure (to be referred to as “repair andstrengthening system components kit” hereinafter) 700 is used to installthe steel plate with sidewall 80 onto the reinforced concrete structure10 including the structure sides 18. The repair and strengthening systemcomponents kit 700 is made up of disassembled components.

That is, the steel plate with sidewall 80 includes the ribbed steelplate 20 and the steel-plate sidewall parts 26 that are integratedtogether, and the steel-plate back face 24 of the ribbed steel plate 20is provided with the guide projection 25.

In the steel-plate support member 50, the support horizontal member 51and the pair of support vertical members 52 are disassembled, and thefastening bolt 72 and the height adjusting bolt 71 for fastening thesetwo components are provided. The support horizontal member 51 isprovided with the guide groove 56. Further, the supporting bolt 60 andthe nut 61 are provided to attach the steel-plate support member 50 tothe reinforced concrete structure 10.

Accordingly, the repair and strengthening system components kit 700 isobtained by disassembling the individual components described above withreference to Embodiments 3 and 5 and then collecting these componentsinto a “components kit”. Therefore, the repair and strengthening systemcomponents kit 700 can be stored in relatively narrow spaces, and isalso easy to transport.

Because these components can be assembled and installed to thereinforced concrete structure 10 to repair or strengthen the reinforcedconcrete structure 10, these components function as the repair andstrengthening systems 300 to 500 for the structure. The sizes andquantities of individual components are determined by the size of theportion to be repaired or strengthened.

Embodiment 8

FIG. 15 is a partially see-through front view for explaining a repairand strengthening system for a reinforced concrete structure accordingto Embodiment 8 of the present invention. Portions that are the same asor equivalent to those in Embodiment 1 or Embodiment 6 are denoted bythe same reference signs, and a description of these portions ispartially omitted. Further, FIG. 15 is schematic only, and not intendedto limit the present invention to the particular forms (such as shapesor quantities) illustrated.

In FIG. 15, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 800 strengthens the reinforced concrete structure 10 byusing a steel grid plate 890.

The steel grid plate 890 corresponds to the steel grid plate 90(Embodiment 6) from which the side portion 98 is removed to leave onlythe bottom portion 97. The steel grid plate 890 includes the gridportion 94 and the plurality of openings 93.

A part of the grid portion 94 of the steel grid plate 890 is in contactwith the structure surface 14 of the reinforced concrete structure 10.

At this time, the filler 30 injected in the openings 93 of the steelgrid plate 890 is in intimate contact with the strengthened area 15 ofthe structure surface 14. Consequently, the grid portion 94 of the steelgrid plate 890 mechanically interlocks with the filler 30, allowingtransfer of shear between the structure surface 14 and the steel gridplate 890. Therefore, the same operational effects as the repair andstrengthening system 100 (Embodiment 1) are provided.

In the above example, the steel grid plate 890 covers the strengthenedarea 15 having irregularities. However, the present invention is notlimited to this. The steel grid plate 890 may cover an area of thestructure surface 14 which has no irregularities.

Further, the steel grid plate 890 may be used also in Embodiments 2 to7, in such a way that the steel grid plate 890 is in contact with thestructure surface 14.

Embodiment 9

FIG. 16 is a partially see-through front view of a repair andstrengthening system for a reinforced concrete structure according toEmbodiment 9 of the present invention. Portions that are the same as orequivalent to those in Embodiment 1 or Embodiment 6 are denoted by thesame reference signs, and a description of these portions is partiallyomitted. Further, FIG. 16 is schematic only, and not intended to limitthe present invention to the particular forms (such as shapes orquantities) illustrated.

In FIG. 16, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 900 strengthens the reinforced concrete structure 10 byusing a steel grid plate 990.

In the steel grid plate 990, the grid portion 94 of the steel grid plate890 (Embodiment 8) is provided with ribs 95.

Some of the ribs 95 of the steel grid plate 990 are in contact with thestructure surface 14 of the reinforced concrete structure 10.

At this time, the filler 30 injected in the openings 93 of the steelgrid plate 990 surround the ribs 95, and is also in intimate contactwith the strengthened area 15 of the structure surface 14. Consequently,the grid portion 94 and the ribs 95 of the steel grid plate 990mechanically interlock with the filler 30, allowing transfer of shearbetween the structure surface 14 and the steel grid plate 990.Therefore, the same operational effects as the repair and strengtheningsystem 100 (Embodiment 1) are provided.

The shape of the ribs 95 is not limited. For example, the ribs 95 may beprotrusions having the shape of a truncated cone, or may be projectionswith a predetermined length. Further, in the above example, the steelgrid plate 990 covers the strengthened area 15 having irregularities.However, the present invention is not limited to this. The steel gridplate 990 may cover an area of the structure surface 14 which has noirregularities. Further, the steel grid plate 990 may be used also inEmbodiments 2 to 7, in such a way that the ribs 95 of the steel gridplate 990 are in contact with the structure surface 14.

Further, the ribs 95 may be formed on both sides of the grid portion 94(not illustrated). At this time, the ribs 95 formed on both sides aresurrounded by the filler 30, allowing strong adhesion between the steelgrid plate 990 and the filler 30, thus promoting the same operationaleffects as the repair and strengthening system 100 (Embodiment 1).

Further, the ribs 95 of the steel grid plate 990 may be formed on theside of the steel grid plate 990 opposite to the structure surface 14,and the ribs 95 may be surrounded by the filler 30 in such a way thatthe side of the steel grid plate 990 without the ribs 95 is partially incontact with the structure surface 14. In this case as well, the sameoperational effects as the repair and strengthening system 100(Embodiment 1) are provided.

Embodiment 10

FIG. 17 illustrates a repair and strengthening system for a reinforcedconcrete structure according to Embodiment 10 of the present invention,in which FIG. 17A is a partially see-through front view, and FIG. 17B isa perspective view of a part of the repair and strengthening system.Portions that are the same as or equivalent to those in Embodiment 8 aredenoted by the same reference signs, and a description of these portionsis partially omitted. Further, FIG. 17 is schematic only, and notintended to limit the present invention to the particular forms (such asshapes or quantities) illustrated.

In FIG. 17, a repair and strengthening system for a reinforced concretestructure (to be referred to as “repair and strengthening system”hereinafter) 1000 strengthens the reinforced concrete structure 10 byusing two steel grid plates 890 (hereinafter, one and the other of whichare to be referred to as steel grid plate 890 a and steel grid plate 890b, respectively). The hang bolt 40 and the nut 41 are not illustrated.

Some of openings 93 a of the steel grid plate 890 a and some of openings93 b of the steel grid plate 890 b overlap (at two locations in FIG.17). A part of a grid portion 94 a of the steel grid plate 890 a and apart of a grid portion 94 b of the steel grid plate 890 b overlap (atthree locations in FIG. 17; hereinafter, the overlapping area is to bereferred to as “lap portion 890 ab”).

At this time, the steel grid plate 890 a and the steel grid plate 890 bare integrated together by the filler 30 injected in the overlappingopenings 93 a of the steel grid plate 890 a and the overlapping openings93 b of the steel grid plate 890 b. That is, the filler 30 injected inthe lap portion 890 ab also functions as a “joint” for transferringforce between the steel grid plate 890 a and the steel grid plate 890 b.

A part of the grid portion 94 a of the steel grid plate 890 a and a partof the grid portion 94 b of the steel grid plate 890 b are each incontact with the structure surface 14, and the grid portion 94 b of thesteel grid plate 890 b is bent at a bending portion 96 b so that in thelap portion 890 ab, the grid portion 94 a of the steel grid plate 890 aand the grid portion 94 b of the steel grid plate 890 b are locatedclose to or abut against each other.

The bend at the bending portion 96 b may be removed. Instead, each ofthe steel grid plate 890 a and the steel grid plate 890 b may be formedin a planar shape so that a part of the grid portion 94 a of the steelgrid plate 890 a is in contact with the structure surface 14, and a partof the grid portion 94 b of the steel grid plate 890 b is opposed to thestructure surface 14 with a predetermined space therebetween.

While the above description is directed to the case of using two steelgrid plates 890, the present invention is not limited to this. Three ormore steel grid plates 890 may be made to partially overlap in a similarmanner.

Further, in the repair and strengthening system 900 (see Embodiment 9),a plurality of steel grid plates 990 may be used, and the plurality ofsteel grid plates 990 may be made to partially overlap in a similarmanner. At this time, the ribs 95 may be provided either on one side orboth sides.

Further, a part of the steel grid plate 890 (Embodiment 8) and a part ofthe steel grid plate 990 (Embodiment 9) may be made to overlap.

INDUSTRIAL APPLICABILITY

According to the present invention, delivery of force between the steelplate and the filler can be improved. Therefore, the present inventioncan be used for a wide variety of applications as a repair andstrengthening structure for a reinforced concrete structure to repair orstrengthen various reinforced concrete structures such as floors, beams,and columns.

We claim:
 1. A repair and strengthening system for a reinforced concretestructure, comprising: a steel plate that is disposed with a space to astructure surface, the structure surface being a surface of thereinforced concrete structure; and a filler that is injected in thespace, wherein a plurality of protrusions are formed on a steel-platefront face that is a surface on one side of the steel plate, and thesteel-plate front face faces the structure surface.
 2. A repair andstrengthening system for a reinforced concrete structure, comprising: asteel plate that is disposed with a space to a structure surface, thestructure surface being a surface of the reinforced concrete structure;and a filler that is injected in the space, wherein a plurality ofopenings are formed in the steel plate, and the openings are blocked bythe filler.
 3. A repair and strengthening system for a reinforcedconcrete structure, comprising: a steel plate that is disposed incontact with a structure surface, and is provided with a plurality ofopenings, the structure surface being a surface of the reinforcedconcrete structure; and a filler that blocks the openings.
 4. The repairand strengthening system for a reinforced concrete structure of claim 3,wherein a plurality of protrusions are formed on a steel-plate frontface that is a surface on one side of the steel plate, and at least oneof the plurality of protrusions is in contact with the structuresurface.
 5. The repair and strengthening system for a reinforcedconcrete structure of claim 3, wherein a plurality of protrusions areformed on a steel-plate back face that is a surface on another side ofthe steel plate, and the plurality of protrusions formed on thesteel-plate back face are surrounded by the filler.
 6. The repair andstrengthening system for a reinforced concrete structure of claim 3,wherein the repair/strengthening system has a plurality of the steelplates, and in one steel plate pair of the steel plates, at least one ofthe openings of one steel plate and at least one of the openings ofanother steel plate overlap each other, and the one steel plate and theother steel plate are integrated together by the filler injected inoverlapping openings of the one steel plate and overlapping openings ofthe other steel plate.
 7. The repair and strengthening system for areinforced concrete structure of claim 2, wherein the plurality ofopenings are formed by enlarging a plurality of slits formed in thesteel plate by stretching.
 8. The repair and strengthening system for areinforced concrete structure of claim 1, wherein the plurality ofprotrusions are formed integrally when the steel plate is manufacturedby hot rolling.
 9. The repair and strengthening system for a reinforcedconcrete structure of claim 8, wherein the plurality of protrusions arespaced by 30 mm to 40 mm from each other, have a height of 2.5 mm to 5.0mm, and have a width of 4 mm to 20 mm, the width being a distance in adirection perpendicular to a direction of the hot rolling at a base ofthe protrusions.
 10. The repair and strengthening system for areinforced concrete structure of claim 1, wherein the steel plate issupported by a hang bolt, the hang bolt being installed in thereinforced concrete structure and projecting from the structure surface.11. The repair and strengthening system for a reinforced concretestructure of claim 1, wherein: the reinforced concrete structureincludes the structure surface, and a pair of structure sides that arecontinuous with the structure surface; the repair/strengthening systemcomprises a steel-plate support member including a support horizontalmember that is disposed in parallel to the structure surface, a pair ofsupport vertical members that are disposed in parallel to the pair ofstructure sides, and a supporting bolt that is installed in thereinforced concrete structure, and projects from the pair of structuresides; the steel-plate support member is installed onto the reinforcedconcrete structure with the supporting bolt that penetrates avertical-member through-hole formed in the pair of support verticalmembers; and the steel plate is installed on the support horizontalmember of the steel-plate support member.
 12. The repair andstrengthening system for a reinforced concrete structure of claim 11,wherein: the vertical-member through-hole is elongated in a directionperpendicular to the support horizontal member; a height adjusting boltis installed to each of the support vertical members, the heightadjusting bolt being movable in the direction perpendicular to thesupport horizontal member and abutting against the supporting bolt at adistal end; and as the height adjusting bolt is turned, the steel-platesupport member is moved in a direction perpendicular to the structuresurface.
 13. The repair and strengthening system for a reinforcedconcrete structure of claim 11, wherein: a guide projection is providedon a steel-plate back face, the steel-plate back face being a sideopposite to the steel-plate front face; the support horizontal member isprovided with a support-member guide groove into which the guideprojection enters; and as the guide projection is guided by thesupport-member guide groove and moves, the steel plate is able to moverelatively with respect to the steel-plate support member.
 14. Therepair and strengthening system for a reinforced concrete structure ofclaim 11, wherein the support horizontal member and the support verticalmembers are detachably coupled by a fastening bolt.
 15. The repair andstrengthening system for a reinforced concrete structure of claim 1,wherein the steel plate includes a pair of steel-plate sidewall parts,the pair of steel-plate sidewall parts being continuous with oppositeside edges of the steel plate and formed on a same side as thesteel-plate front face.
 16. The repair and strengthening system for areinforced concrete structure of claim 2, wherein: the steel plate isbent into a U-shape in section that includes a bottom portion and a pairof side portions; a bar member is installed to penetrate a structurethrough-hole formed in the reinforced concrete structure; and as the barmember penetrates the openings, the steel plate is secured onto thereinforced concrete structure.
 17. The repair and strengthening systemfor a reinforced concrete structure of claim 1, wherein the steel plateis made of plain steel, high tension steel, stainless steel, orweathering steel.
 18. The repair and strengthening system for areinforced concrete structure of claim 1, wherein the filler is mortar,shrinkage-compensating mortar, polymer cement mortar, resin mortar,fiber reinforced concrete, superplasticized concrete, high-strengthconcrete, an epoxy resin injection material, a polyurethane resininjection material, or a sodium silicate injection material.